


Brothers at Heart

by PistachioShells (orphan_account)



Series: UnderBuilt Canon [1]
Category: Undertale (Video Game)
Genre: Gen, Original au, Overprotective, Robot AU, Short, Tired Papyrus, alternate universe- robot/machine, future series, notcybertale, racism? Tw, violence tw
Language: English
Status: Completed
Published: 2020-07-18
Updated: 2020-07-24
Packaged: 2021-03-04 23:48:02
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 4
Words: 2,656
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25274923
Author URL: https://archiveofourown.org/users/orphan_account/pseuds/PistachioShells
Summary: UnderBuilt Sans and Papyrus’ backstory. UnderBuilt is a personal au, which I’d previously named Bottale! (I didn’t know it was already an existing au, hehe-)Teen and up for potentially triggering subjects.Undertale is by Toby Fox, and UnderBuilt is by me, PistachioShells!
Series: UnderBuilt Canon [1]
Series URL: https://archiveofourown.org/series/1831090
Kudos: 7





	1. The Prototype

**The Prototype**

Alphys shuffled scraps and wires around in the dump. Bored out of her mind, she just wanted something to work on. Maybe a solar panel, a reactor or generator of some sort-

oh!

Well, never mind.

Her muddied claws dug up an old robot; it was heavily damaged, but Alphys wasn’t one to give up a challenge. You know, a challenge that didn’t involve other monsters. Eek, no.

Plopping her newly retrieved specimen on a workbench, she wiped off her claws and picked up a screwdriver. Time to see how this thing ticked! Removing panels, one by one, it became increasingly obvious just how old it was. Though made of what seemed like stainless steel, many parts were rusted out, or even rusted together to the point where Alphys had to lever them off. Water was pooled up almost everywhere, it was so poorly designed. In fact, who DID make this thing? She picked up one of the panels. Nothing.

Filled with more curiosity than ever, Alphys started going through it even faster. After all, she didn’t really have any friends to talk to, unless you counted maybe King Asgore. And even then, he was really just her boss... who hadn’t told her to do anything in months... she got bored and antsy quickly.

She growled. One of the only functioning parts that remained was what seemed to be an artificial soul, older than any she’d encountered. ‘Proto’ was written in what seemed like... sharpie... jeez, whoever built this had no respect for machinery!

Managing to salvage the fragile soul, she set to replicate ALL the other parts. She had her work cut out for her! First, though..

Alphys ripped the lid off of her ramen. She slurped up the hot noodles, slightly regretting eating it so fast, and looked around her workplace. Maybe she should dust... Eh, she could wait another month. It wasn’t that bad. Yet. 

She looked back to the parts. She wanted to replicate it as close as possible- despite it being horribly done, it was essentially a relic. She wanted to, in a way, see how it looked before it was so horribly rusted out... Well, she had plenty of time to think about while she worked. It would take a week, at least!

Far more than a week later, Alphys dropped her tools in front of the finished creation. It looked a bit strange, to say the least. It seemed to be a skeleton, with the proportions of a short, young adult. Or maybe a child. It was honestly hard for her to tell, since she wasn’t exactly a biologist.

From what she could see, it really WAS a prototype. It didn’t seem to have a specific purpose, other than for experimenting. Truly disgraceful, to the creator! She tapped on the shoulder. It seemed sturdy enough to function, at least. She’d let it charge, and now.. it should be ready for testing. She turned on the power.

Their two eyelights glowed. Their eyes were huge, and, frankly? They were pretty cute! However, they didn’t move.

> A little confused, Alphys cleared her throat. “Can you hear me? Come over here, if you can. Please?”

Immediately, the little skeleton machine slid off the bench and onto the ground. The quickly crunched over, coughing into their elbow. A black liquid splattered over their bones, seemingly sick. Alphys, panicking a little, gave them a tissue. They wiped their mouth clean.

> ”Uhm,” Alphys started. “Can you talk? Please tell me your name. Er, please! And, uh, thanks?” She buried her face in her hand. God, she had no social skills.
> 
> However, they complied. They spoke quietly and hoarsely; “ I can talk. M- *cough* m-my name is Sans.”
> 
> ”Sans? What a strange name...”

**Notes for the Chapter:**

> I’m back writing Undertale! I’m sorry if it looks weird, but it’s been a while. It was sitting in my drafts for a while before I decided to just post it. Thanks for understanding!


	2. New Soul

**New Soul**

> ”What’s that?” Sans questioned, yet again.
> 
> ”Well, it’s a robot. Like you! I j-just haven’t finished restoring them yet.”
> 
> ”Kinda looks like a skeleton.”
> 
> ”YOU look like a skeleton, Sans.”
> 
> ”Yeah but they seem like... more... real.”
> 
> ”More proportional, I know.”

Ever since Alphys had brought Sans back to functionality, she quickly discovered that he was just as curious as she was. It didn’t seem like he’d ever been booted up; almost everything, save the English language, was new to him.

> ”Alphys, what’s that?”
> 
> ”That’s rust. It ruins the metal.”
> 
> ”Did I have rust when you found me?”
> 
> ”Yes, but it was-wasn’t as bad.”

Luckily for her, he seemed to have just as much (or less) social skills than her. It made her feel a bit more comfortable, knowing that he wasn’t going to judge her.

> ”Alphys, I’m gonna recharge.”
> 
> ”Okay, you do that.”

After a few more weeks, Alphys had really made progress on both of them. However, it was without a doubt that some of Sans’ programming had gotten fried...

> ”Uh, Sans, that’s not really how you do that...”
> 
> ”Do what?”
> 
> ”Well, you aren’t supposed to eat ketchup with a spoon... or on its own...”
> 
> “Why not?”
> 
> ”Well it’s unhealthy!”
> 
> ”But I’m a robot!”
> 
> ...
> 
> ”Sans, what-“
> 
> ”I found them outside.”
> 
> ”We haven’t seen wolves in hundreds, if not thousands, of years! How did you get one this small?!”
> 
> ”They were outside!”
> 
> ...
> 
> “HOW DID YOU FIND AN AVOCADO UNDERGROUND?!”
> 
> ...

There were also a few other... oddities.

First off, Sans knew sign language, which had been lost long ago, since most monsters could easily get help for things like deafness or muteness.

Secondly, Sans had extremely low battery capacity and hp. As in, next to none. With 1hp and about 2 hours of battery life, she had to be extremely careful.

Finally, Sans could ‘teleport’. This in itself was weird, but considering how they constantly found things that were either lost to time or nonexistent, it made her wonder what exactly was possible...

> He poked her arm. “Alphys? We’re out of ketchup again...”
> 
> She sighed. It’d only been a week... “I’ll have to go out again soon anyway. There’s someone I have to meet.”
> 
> ”Who is it?”
> 
> ”Just... someone. Afterwards, I’ll finish up this project and they should be ready to go.”
> 
> Sans smiled. “Okay!”


	3. To be a Hero

**To be a Hero**

> ”Alright, Sans. Just wait here, I’ll be back soon.”
> 
> ”How long?”
> 
> ”I don’t... know. A while, I think.”
> 
> ”Can I come?”
> 
> ”UHH I think, uh, that would be... a bad idea, she doesn’t know you, uhm... Yeah. For now, just stay here. You’ll meet her... eventually!”
> 
> ”O...Kay.”

Alphys hoisted up the other robot onto the stand, hooking it up to an outlet.

> ”They’ll be charging while I’m gone. We can try booting them up when I get back.”

Alphys tossed on her lab coat, putting a mint into her mouth. As she left, Sans watched her. _Well, I don’t have to stay here if she doesn’t notice I’m gone,_ Sans reasoned. _I can follow. I dont see any reason not to!_ And so, he left. 

She took a deep breath. It was just to help her with an injury, that’s all. That’s it! That’s all. Alphys groaned, smacking herself in the head. Well, she surely didn’t feel that way... She looked up at the door, which suddenly looked much more intimidating.

Sans watched from behind a tree. Who was that? Why was it raining without clouds? Why... did the water hurt? He looked at his arm, which sent shocks whenever a drop fell on it. OH. _SH*T! I’M NOT WATERPROOF!!_ Sans began panicking a little. He should’ve brought a raincoat or a blanket or something...

He heard a crunch behind him. He looked back, to see a giant monster... well, they were giant to the 4’11” robot. After all, the only other person he’d really seen was Alphys, who looked even shorter since she was always hunched over her work...

Snapping him from his train of thought, the big monster pushed him to the ground. Though Sans wasn’t hurt, he was definitely scared... The monster smiled devilishly at him. 

> “Is that a robot? God, he looks like a kid. It almost makes me feel bad for him. Too bad I need the parts...”

It was clear he was enjoying this. _Feel bad my a*s,_ Sans thought. He glared at the bigger monster, too scared to get up and run. The monster picked him up by the neck. 

> “Pff, what are you made of, aluminum? One hand! Honestly, you’d think something like you would be better built.” They grabbed at his arm.
> 
> ”W-wait! I’m sorry!” Sans spluttered, not even sure what he was sorry for. 

Suddenly, another crunch came from the forest. And another, and another. Someone was running towards them. 

> “H-HELP! OVER HERE!” Sans screamed. The monster rolled their eyes.
> 
> ”Do you really think living things like us care about you tin cans?” They spitted.

However, their words didn’t stop whoever it was. Sans hoped for safety, as blackened tears rolled down his face, staining his metal cheeks. 

> “LET GO OF HIM!” A voice boomed. They sounded young, and the monster laughed. 
> 
> “Pff, a kid. They don’t know any better. Just know that, you piece of crap.”

Out of the woods, they appeared. Unlike Sans’ blue eye lights, theirs were black... but soon burned into an intense blood-orange. A scarf of light panels were wrapped about their neck, and they were donned in armor. Unfortunately, they were PISSED.

> ”LET HIM GO.” They demanded. The monster smiled.
> 
> ”Look kid, it’s just a robot. See? Its hands are cold.” They put one of Sans’ hands in front of them, but they didn’t feel them.
> 
> ”I told you to let him go. Please.” Their face remained unchanged.
> 
> The monster growled. “Who do you think you are? You should be respectful to your elders!”
> 
> They stepped forward. “My name is Papyrus. And, in case you haven’t noticed, I’m a robot too.” Papyrus summoned two skull-shaped blasters, with a single sniper-like barrel. “Let him go.”

They took a step back, but Papyrus took a step forward. They tried to take Sans and run, but Papyrus grabbed a hold of their soul with some sort of blue magic. The monster finally let go of Sans, dropping him to the ground.

Papyrus ran forward and caught him, unconscious now from the stress. He saw the tears, and the pain that resided in his face even as he slept. Slowly setting him down, he brought his blasters ever closer to the monster’s face. 

> “Run.” He growled. “Run if you want to live.” The orange in his eyes turned a violent shade of red, along with the eyes of his blasters. They ran, and ran far away from them...

Papyrus picked up Sans, carrying them back to the lab. He didn’t know why he was brought here, but he knew why he would stay.


	4. The Dove and the Crow

**The Dove and the Crow**

Alphys looked at the two robots in front of her, both of which were shifting around awkwardly.

She sighed.

> ”I really wanted you guys to stay home. This was the reason why! Sans, you should be happy Papyrus saved you.” He nodded meekly.
> 
> ”And, Papyrus, why did you go out if you saw nobody home? I know you didn’t really know any better, but...”
> 
> Papyrus looked down. “Honestly, it just felt like I was supposed to. I don’t know why.”
> 
> Alphys nodded. “Al...right. Alright. That’s understandable. Robot programming. That sounds right, I think. Programming. Maybe?” She shook her head and sighed again. “Sans, you know how delicate you are! You really shouldn’t have gone out...”

Sans looked to the side. Papyrus had thrown a rain coat over him, and thought it was a bit big, it definitely did the job. It had a strange, vaguely familiar logo on it- Alphys assumed that she saw it somewhere before. At some point.

Papyrus was substantially taller then Sans, at MINIMUM one foot taller. His armor was made of a lightweight steel, just like Sans’ body. Both were similar in some ways, different in others. Papyrus didn’t have Sans’ knack for jokes and ketchup, but was alike in the fact that both of them could teleport, and they had similar faux souls; those souls were the most advanced part of both of them. They almost seemed real, and could feel, and could- well, do anything a normal soul could. So why was Sans so weak?

> Alphys looked up at Papyrus. “I know you probably won’t be able to answer, but do you know anything about Sans?”
> 
> Papyrus looked up. “Other than what you told me? Unfortunately, no. I wish I did.” He looked at Sans, who was gently putting ketchup on his finger and lapping it up. He frustrated Papyrus already, but... after seeing what monsters could do to such a weak robot...
> 
> Alphys glanced worriedly at Sans before turning back to the other skeleton. “From what I saw written on one of his panels, it says his name is Proto, but he calls himself Sans. He doesn’t recognize G Labs, either, and I’ve never heard of them... Which is weird, because no lab like that is here Underground. Do you have any ideas? You seem to remember more than him.”
> 
> Papyrus shook his head. “The Lab sounds familiar, somehow. I don’t really know anything other than that. Hopefully we’ll remember something.”
> 
> Alphys sighed. “I just got a new project from the King, but I can’t watch him all the time. Papyrus, I know this might be asking a lot, but can you watch over Sans?”
> 
> Papyrus immediately smiled. “I’d rather have no other job in the world.”
> 
> Alphys smiled, too. “I know, its weird, especially since you two aren’t related closely at all, but... thank you. Thanks!”
> 
> Papyrus nodded, looking to the skeleton next to him, which is now fast asleep, clutching a ketchup bottle in his hands.

Sometime later, Sans woke back up, and Alphys had given them all the information on them she could find... which was...

> ”That’s distressingly little,” Papyrus said. Sans nodded along with him.
> 
> For what was probably the hundredth time that day, Alphys sighed. “I know.”
> 
> Sans pointed at the manufacture dates. “There’s a hundred years difference! A HUNDRED!”
> 
> Papyrus nodded. “And you’re older than me. By about a hundred years.”

Sans looked through the paperwork, absorbing it faster than any machine Alphys had seen. Papyrus, this time, was lazy, deciding that it wasn’t really in his best interest to discover their past.

> “According to this, I was the first fake soul manufactured... and no others used the same parts...” Sans went quiet.
> 
> ”I guess that means no real family,” Alphys said, receiving a short glare from Papyrus.
> 
> ”I was built trying to make the best of everything, since I was the first. And... They really only succeeded with my brain, my memorization, memory... huh! Look at that, I’m smart!” Sans smiled at his little joke, causing a worried look from Papyrus.
> 
> ”Papyrus... you were a therapy bot. To help and defend people, but ‘he ended up being protective of really only one person. Though sympathetic, he still only cared for that one person, like a loyal cat...’” He looked up at Papyrus. “So I guess that means you got really protective of me?”
> 
> He nodded. “Seems so. Because I was also a bit of experiment, there was none manufactured like me either. It says here.” Papyrus pointed at the thin paper.

Alphys looked at the two bots. They had no real family, no lab, and nobody to rely on except for her, who was constantly working. Life really was unfair, huh?

> ”We can be brothers...” Sans reasoned. “I mean, we look kinda alike.”
> 
> Papyrus looked at his forearm. “You’re right about that, but... Lots of monsters look alike but aren’t related.”
> 
> ”Siblings like to protect each other sometimes too, right? I think?” Sans replied.
> 
> The other nodded. “I guess we are kind of... like siblings, or brothers.”

The two smiled at each other. Happy, Alphys got up. Looks like she didn’t have to worry about them as much as she thought.

**Notes for the Chapter:**

> Thank you so much for reading! Feel free to use UnderBuilt Sans and Papyrus in any work, as long as they’re credited to me. As a bonus, they’re both now on ArtFight! If you need a reference, just pop on over!
> 
> Sans: https://artfight.net/character/1233957.sans-underbuilt
> 
> Papyrus: https://artfight.net/character/1233966.papyrus-underbuilt


End file.
